U.S. Pat. No. 3,770,185 provides for a straw opening means wherein parallel score lines are cut from one side and a circular score line is cut from the opposite side of one vertical wall above the gable, each to a depth of from 40 to 75 percent of the wall thickness. Such score lines form a tear strip extending from the upper vertical edge, along the width of the vertical wall and onto one gable. A "thumb notch" is formed on the uppermost edge of the other vertical wall to facilitate the opening process. Once the tear strip is torn away along the lines defined by the parallel score lines, a plug of material encompassed by the circular score line remains intact with the tear strip to expose a hole for receiving a straw.
U.S. Pat. No. 4,244,474 provides for a straw opening means wherein spaced apart score lines are formed to extend laterally from the edge of a conventional gable top roof panel interconnecting-side seam flap, to a depth of at least halfway through the paperboard, forming a tear strip such that when the tear strip is peeled or torn away past the free edge of the side seam panel, a weakened area is exposed which may be penetrated by the pressing of a straw thereagainst. In one embodiment, an extended tab is formed by notching the side seam panel of an adjacent carton blank in the cut-off operation from a paperboard roll.
U.S. Pat. No. 4,318,479 provides for a straw opening means wherein a tab and tear strip are formed on the panel overlying the side seam panel bearing an arcuate notch comparable in shape to the tab.